1. Field of the Invention
The present invention relates generally to the field of projection systems. More specifically, the present invention discloses a ceiling-mounted projector having a retractable periscope mount.
Statement of the Problem. Video projectors were first mounted to the ceiling as a convenient method of permanent installation. It allowed for the projector to be out of the way (i.e., above the audience) and immediately available. Three problems were created with this approach. First, it is visually unappealing. Many projectors are mounted in corporate board rooms or company training/sales rooms that are custom designed and valued at hundreds of thousands of dollars. The always-present projector, with cables hanging out, can be a significant distraction. The second problem is noise. Many projectors emit very disturbing noise that can interfere with board meetings, training sessions, teleconferencing, etc. This third problem is the theft. Video projectors are expensive and quite a target for thieves. Conventional ceiling-mounted projectors make easy targets.
One attempt to address some of these problems is the projector lift mount. The mount and projector are installed above the ceiling line. The mount lowers the projector during use. However, the structure used to lower the projector is large and unattractive, which still makes the room unattractive during use of the projector. This approach also does nothing to alleviate the noise issue.
Another approach employs a projector mounted above the ceiling line. The projected image bounces off an upper fixed mirror to a second mirror attached to a ceiling tile that rotates open. Due to the nature of the second mirror rotating about a fixed point, this has proved to be difficult to accurately set and maintain a precise image to the target screen.
2. Prior Art
The prior art in the field includes the following:
InventorPatent No.Issue DateHartwig3,277,780Oct. 11, 1966Nemec et al.3,488,115Jan. 6, 1970Johnson et al.4,124,285Nov. 7, 1978Lander5,160,951Nov. 3, 1992Gelman5,402,192Mar. 28, 1995Matsumoto et al.5,755,500May 26, 1998Smock et al.5,993,011Nov. 30, 1999Enochs et al.6,379,012Apr. 30, 2002Soper et al.Pub. 2003/0160947Aug. 28, 2003
Johnson et al. disclose a projector system for projecting a pattern on textile fabric on a cutting table. The projected pattern can be moved laterally across the width of the fabric to determine whether or not flaws in the fabric will be present in the area to be cut out according to the pattern. The projected image is reflected by two fixed mirrors 110 and 118 in a periscope-like arrangement.
Smock et al. disclose a projector mount system positioned within a ceiling grid with a vertical ventilation duct and exhaust fans. The image from the projector is reflected downward by an upper mirror onto a lower mirror that pivots.
Enoch et al. disclose an overhead projector mount system that employs a tilting mirror to project the image.
Nemec et al. and Soper et al. show examples of retractable overhead projectors with folding mirrors. The remaining patents by Hartwig, Lander, Gelman and Matsumoto et al. are only of passing interest.
Solution to the Problem. None of the prior art references discussed above show a ceiling-mounted projection system with a mirrors mounted in a periscope arrangement that can be raised to an inconspicuous position when the projector is not in use, and lowered below the ceiling to project images on a viewing surface in the room when the projector is in use. The present invention solves the problems of appearance, noise, and susceptibility to theft associated with conventional ceiling-mounted projection systems, while maintaining an accurate and reliable video image on the target screen.